Method and apparatus of indirect-evaporation cooling

ABSTRACT

The within invention improves on the indirect evaporative cooling method and apparatus by making use of a working fluid that is pre-cooled with and without desiccants before it is passed through a Wet Channel where evaporative fluid is on the walls to take heat and store it in the working fluid as increased latent heat. The heat transfer across the membrane between the Dry Channel and the Wet Channel may have dry, solid desiccant or liquid desiccant and may have perforations, pores or capillary pathways. The evaporative fluid may be water, fuel, or any substance that has the capacity to take heat as latent heat. The Wet Channel or excess cooled fluid is in heat transfer contact with a Product Channel where Product Fluid is cooled without adding any humidity. An alternative embodiment for heat transfer between adjacent channels is with heat pipes.

[0001] The applicant claims priority of Provisional patent applicationSerial No. 60/221,264, filed Jul. 27, 2000, entitled “METHOD OFINDIRECT-EVAPORATION COOLING”, inventors, Valeriy Maisotsenko, et al.

FIELD OF INVENTION

[0002] 1. The present invention relates to methods ofindirect-evaporation cooling of fluids and to heat exchange apparatusfor affecting these methods.

[0003] 2. The invention can be used for air conditioning, as well ascooling liquids and gases in different technological processes. It canbe used to cool materials that can be conveyed along the heat transfersurfaces of the apparatus by methods other than fluidization.

BACKGROUND

[0004] The use of Evaporative methods to cool gases is well-known. Theuse of adjacent channels or heat transfer services to allow anevaporation in one channel to provide cooling for material in the secondchannel is also well-known, see. Niehart U.S. Pat. No. 2,174,060.

[0005] The methods and apparatus to cool air through evaporation haveproved useful over many years. However they have certain drawbacks andlimitations due to their designs.

[0006] There is known in the art a method of indirect-evaporationcooling of air, comprising cooling the flow of outside air over a heatexchange apparatus (USSR Patent No. 979796). The outside air is pushedover a heat transfer surface, or moisture proof plates of the DryChannel. The apparatus is comprised of a number of verticalmoisture-proof plates which divides alternately Dry Channels and WetChannels. At the outlet from the Dry Channel the flow of air is dividedinto two flows, namely, the cooled product flow and working flow to theevaporation or wet channel. The cooled flow goes to the consumer, andthe evaporative flow is directed in counter flow of the Dry Channel, inthe Wet Channel. The flows are controlled by the creation of aerodynamicresistance at the Dry Channel outlet. The heat transfer between the dryand Wet Channels causes heat to be drawn out of the outside air in theDry Channel across the heat transfer surface and into the evaporation ofthe water in the Wet Channel. Cooling the air by the heat transfersurface occurs from the inlet of the Dry Channel to the exit. Thisallows air temperatures at the end of the Dry Channel to approach thedew point temperature of the air entering the Dry Channel.

[0007] The essential disadvantages of the described method and theapparatus for effecting same are: 1) the Product Fluid can not be cooledeven in an ideal case lower than the temperature of tile dew point ofoutside air; 2) the impossibility of cooling materials other than air orgas and; 3) difficult to realize cooling process for use in vehicles.

[0008] In addition to the above indirect-evaporation cooler there is aconceptual method and design apparatus for Evaporating and Cooling Waterdisclosed in Maisotsenko patent USSR Patent No. 690271 and USSR PatentNo. 641260 where by single pass of air is used to cool water. In thismethod and apparatus the outside air flow is pushed down a Dry Channelwith a heat transfer surface between the dry and wet channels and turned180 degrees at the end of the channel and pushed up in counter flowacross the water wetted heat transfer surface. Evaporation of water fromthe Wet Channel then draws heat across the heat transfer surface coolingthe air in the Dry Channel and also cooling the water in the WetChannel. Enough water is drawn over the Wet Channel to allow evaporationand collection of cooled water at the bottom of the channel whichbecomes the cooled product. Cooling the air in the Dry Channel allowsfor water temperatures at the bottom of the channel to approach the dewpoint temperature of the outside air.

[0009] The essential disadvantages of the described method and theapparatus for effecting same are: 1) the water being cooled can not becooled even in an ideal case lower then the dew point temperature ofoutside air; 2) The ability to cool only water; 3) This process does notuse an induced draft exhaust system and; 4) The description of thematerials and accessories needed to design and make the cooler make forimpractical application.; 5) Cooling potential of this evaporationprocess is limited; 6) The heat transfer rate in the channels,especially the Dry Channels is low.

[0010] Rotenberg U.S. Pat. No. 5,187,946, which is copied from Russianpatent 2046257 Maisotsenko, there is disclosed a Wet-Dry Channel heatexchange system with an evaporative cooler. This does not address theissues of the limitation of ambient air, the limited efficiency of thisdesign or the separate product channel being cooled by the wet channel.

[0011] The use of desiccants in evaporative coolers is common, seeBelding U.S. Pat. No. 6,050,100, where the desiccant dehumidifies theair, both the air that goes to a dry side of an indirect evaporativecooler and the air that is separated and sent to the wet side toevaporate the water and cool the dry side air flow for later use. Thedesiccant is by way of a desiccant wheel. Additionally, the use of thedesiccant and separately treating the two air streams in Belding yieldsa primary stream for the dry side that is more humid and cooler than thedrier and warmer secondary stream that is used for the wet side.

[0012] Unlike the disclosed invention herein, Belding does not use thesame flow for the dry and wet side flows. As a result, the cooling isnot great and there is no separation of product so only air can becooled. Finally, the method requires complex components and separatetreatment of the flows with added mechanics and energy requirements.

[0013] Lowenstein in U.S. Pat. No. 5,351,497 and his paper on “SeasonalPerformance of a Liquid Desiccant Air Conditioner” ASHRAE Symposia 1995makes use of liquid desiccant on the dry side of an indirect evaporativecooler. Similar to Belding, the dry side air is separate and is thecooled product air.

[0014] Lowenstein uses the liquid desiccant to dehumidify the desiredair flow for a living area, and the evaporative cooling is used to aidin absorbing the latent heat that is released by the dehumidification.

[0015] Lowenstein's absorber, throughout makes use of liquid desiccantfor dehumidifying air, does not make use of the unique feature of thewithin application. It does not give the advantages of lower temperatureand controlled humidity.

[0016] Separate absorbers, using liquid desiccants were also discussedin Martinez and Khan, “Heat and Mass Transfer Performance Analysis of aCompact, Hybrid Liquid Desiccant Absorber”, 1996 IEEE. The discussionteaches a result contrary to the within disclosure that such an absorbercould not be used alone to condition and cool air for living space.

[0017] The objectives of this invention is to make an improved methodand apparatus for evaporation of a liquid to provide cooling for gases,liquids or other materials. The invention allows for cooling to a lowertemperature than other methods. Its further objective is to make use ofthe cool product gas flow to cool other materials in an improved waywithout adding vapor or humidity to the product.

[0018] Further objectives of the invention is to make use of dryingagents or desiccants to enhance the efficiency of the invention and itsability to cool. A further innovation is to male use of solid desiccantson a membrane or substrate to allow transpiration of vapor and fluidthat is absorbed in the dry channel by the desiccants and then releasedin the wet channel by evaporation processes and thus cool the membraneand the dry channel.

[0019] The water vapor transpires through the solid desiccant andmembrane.

[0020] Additional objects of the invention are to allow the desiccantsto be concentrated and recycled to provide more efficiency to the cycle.The invention uses the recycling of the desiccant in combination withthe use of the desiccant as part of the wet channel to accomplish bothobjects.

SUMMARY OF INVENTION

[0021] The main object of the invention is to provide an economical andenvironmentally safe method of cooling by indirect-evaporation and heatexchange apparatus, wherein the Product Fluid can be cooled to or lowerthan the dew point temperature of outside air. The object set forth issolved in different ways by using a core piece of heat and mass exchangeapparatus in combination with the cooling process or processes that aredesired. This core piece of apparatus can deliver cooling fluid byeither producing cooled liquid or cooled gas.

[0022] The core of the apparatus passes Working Air along a Dry Channelwith one side of a heat exchange membrane, then turns the flow 180degrees and passes this same flow along a Wet Channel in counter flowwith the same heat transfer membrane but on its opposite side.Evaporation cooling in the Wet Channel cools the Working Air in the DryChannel. The Product to be cooled can be: 1. By the passing of theProduct to be cooled through a third channel in heat transfer contactwith the Wet Channel. 2. An excessive amount of Evaporative Liquid,(being drained off after cooling and passed through a Product HeatExchanger like water, liquid desiccant, or liquid fuel 3, or othervolatile liquid under the applicable pressures). A portion of theWorking Air may be drawn out of the apparatus and used directly as aProduct.

[0023] The unit can be built in a bank of channels. When the Product tobe cooled is set in a channel along side the Wet Channel, it may also bein heat transfer contact with tile Dry Channels due to the succession ofunits.

[0024] The fluid exiting the Wet Channel surface is considered theExhaust. The difference in the total energy between the Working Airentering the Dry Channel and leaving the Exhaust is the Product coolingenergy available. This is generally measured by the difference inenthalpy and flow. The Exhaust enthalpy is ideally limited by theWorking Air temperature entering the Dry Channel at its correspondingsaturation enthalpy.

[0025] The importance of pre-cooling the air before turning it to theWet Channel and then obtaining lower temperatures can be understood byrealizing that the Wet Channel Working Air starts at the lowesttemperature attained in the Dry Channel, generally approaching the dewpoint temperature of the outside air. Before the Working Air enters theDry Channel it's temperature is generally at the outside airtemperature. In all indirect-evaporation cooling apparatus for coolingoutside air, other than described here, Working Air (used inevaporation) and product air temperatures start at the same point, theoutside air temperature, forcing the temperature to approach the higherwet bulb temperature rather than the dew point temperature. Much lowertemperatures can be realized with the use of desiccants to dry air inthe Dry Channel, or by pre-cooling before going to evaporation as setout here, and lower the dew point temperature attainable.

[0026] The main differences between this apparatus and method andprevious art are: 1. The means to create a workable method that willfunction in industry that is both efficient and economical tomanufacture. 2. The wide use of fluid types in all channels. TheEvaporative Liquid used in the Wet Channel for transpiration cooling canbe any thing that will evaporate into the air under the ambient pressureand temperature. The Dry Channel and or the Product Channel of thismethod can also be a drying channel with the use of a desiccant on theheat exchange surface, or on a different surface within the Dry orProduct channel, either liquid or solid to dry the air out while beingcooled at the same time. This core design allows for many differenttypes of fluids to be used and effective cooling at low cost. 3. Thecore method allows for a wider variety in design considerations forcooling different types of products. 4. The heat transfer surfaces onthe walls can be varied from impermeable, to micro-sieve, or toperforated. Perforations or capillary channels allows for transpirationconductively from the Dry Channel to the Wet Channel. This hasadvantages in heat transfer and in efficiencies.

[0027] There are many variations that can be used with this core methodof the invention that are described here after. Tile variations fit thewide variety of applications the core method can be used in.

[0028] It is always advantages to wet both surfaces of the Wet Channel,both the Dry Channel-Wet Channel heat transfer membrane or wall and theWet Channel-Product heat transfer membrane or wall, (when a ProductChannel is used,) to improve the heat transfer rate.

[0029] In high humidity climates it is sometimes advantages to heat theoutside air entering or moving through the Dry Channel. At a higherheat, with no change in humidity, there is a greater latent heatcapacity due to the ability to take on more moisture before saturation.It is approximately five times faster than the energy spent to gainhigher temperatures.

[0030] Drying the air could be with desiccants such as Lithium chloride,bromide, calcium chloride, glycol, triethylene glycol etc. This allowscooling below the dew point temperature of outside air when combinedwith desiccants before or in the Dry Channel because it reduces themoisture content and thus increases the latent heat potential capacity.

[0031] In addition liquids, in the applicable pressure and temperature,with dew point temperatures less than that of water in air, such asgasoline, can be used in the Wet Channel. The fluid may be any suitablefluid that has a high vapor pressure at the ambient temperature andpressure so as to enhance the evaporation and thus take the heat oftransformation from the remaining fluid.

[0032] The Working Air can be dried with a desiccant and then passedthrough the Dry and Wet Channels. This has the dramatic effect ofreducing the temperature of the Working Air and therefore the minimumtemperatures that can be obtained. The Product cooling available is thedifference between the total energy, enthalpy and flow rate, of the hotWorking Air in the Dry Channel and the total Exhaust energy leaving theWet Channel.

[0033] The method can be effectively used to cool water for power plantsand other typical cooling applications with return water temperaturescloser to the dew point temperature of the outside air rather than thewet bulb temperature. In this case the Working Air is precooled in theDry Channel and humidified in the Wet Channel. In many uses thetemperature of the water to be cooled is warmer than the outside air.This added heat works to the coolers advantage as the temperature of theWorking air will be increased which will also increase the availablecooling energy. The use of desiccants to dry the air would lower thetemperatures of the cooling water further as this is a greater capacity.

[0034] The liquid desiccant can be placed in the Dry Channel increasingthe heat transfer rate from air to desiccant and desiccant to the heattransfer surface by five to ten times. This allows: 1. The temperatureof the exhaust air to more closely approach the air temperature enteringthe apparatus. 2. The relative humidity of the exhaust to approach thesaturation point, and, therefore, increases the energy available forcooling of the product.

[0035] Heat pipes can be used between the Wet and Dry Channels, and theProduct Channel as well, if desired, creating the need for only onechannel for each. This allows for easier configuration of a purelycounter flow arrangement of the method.

[0036] In addition, using a desiccant in the Dry Channel providescontinuous cooling of the desiccant and therefore increasing itsabsorption capacity and rate, drying the air faster and to a lowertemperature.

[0037] Regeneration of the desiccant can take place within the coremethod with the use of a porous heat exchange panel between the Dry andWet Channels. This panel would be designed to allow water absorbed bythe desiccant to be drawn directly to the waterside through the panel bymeans of: 1. The lower pressure on the waterside. A pressure drop doesneed to be created between where the Dry Channel ends and the WetChannel begins. The dry side may have forced draft fans and the exhaustmay have an induced draft fan to create a larger pressure drop. 2. Bythe lower density of water on the waterside causing the water in thedesiccant to want to move to the Wet Channel. 3. By the direction of theheat flow to the waterside. The porosity may be to water in liquid orvapor phase.

[0038] Depending on the Product to be cooled the Product Channel couldhave a desiccant used for drying and cooling the product as well.

[0039] The regeneration process does have a small loss in energy due tode-mixing of water moving from the desiccant to the Wet Channel, fromliquid to liquid, but not going through a phase change. When the exhaustair absorbs this water a vapor change would take place creating apositive energy flow for cooling. The heat transfer rate will be largerdue to the lack of a boundary layer in the channel separation wall andthe direct connection of water to both sides of the membrane.

[0040] Solid desiccants can be used for the heat transfer surface in theregeneration process. Dry desiccants have the advantage of no heat lossfrom cooled desiccant flowing from the Dry Channel and carrying off someof the cooling energy. However the heat transfer rate from the WorkingAir to the desiccant is less with a dry desiccant. This desiccantregeneration and drying system could also be used in the ProductChannel.

[0041] The core method can be efficiently used for air conditioning andcooling systems where liquid fueled engines are used such as in avehicle. The Evaporative Liquid in the Wet Channel becomes fuel. The DryChannel takes in outside Working Air for pre-cooling and passing throughthe Wet Channel. The Product Channel in heat transfer contact with theWet Channel is cooled. In addition, it is possible to use a solid or aliquid desiccant in the Dry Channel, and liquid fuel and water to theworking air in the Wet Channel simultaneously increasing the potentialenergy of cooling, due to the increased vapor pressure. In addition thefluid in the Dry Channel can be heated for the Dry Channel, before,during or at the end, with exhaust gases from the engine to provideadditional vapor potential and thus, latent heat capacity of the workingair and cooling product when water is being added to the Wet Channelwith the liquid fuel. The desiccant can be re-concentrated with the heatsource being the exhaust gas of the engine.

[0042] The addition of water in the Wet Channel will produce water vaporin the fuel-air mixture, which is directed to the engine, and it helpsto improve the combustion process in the engine of a vehicle.

[0043] With vehicles that do not use enough fuel to cool a vehicle, orelectric vehicles, core method with water/desiccant system can be used.

[0044] Creating a lower pressure in the Wet Channel will increase thevapor drive from water to the air. Increasing the pressure in the DryChannel will increase the vapor drive to the desiccant. Pressurizing theDry Channel and pulling a partial vacuum on the Wet Channel will requirethe insertion of a baffle between the channels to regulate the WorkingAir flow rate.

[0045] Recycling can be accomplished by use of liquid desiccants.Diluted liquid desiccants can be used in the Wet Channel with dry air toremove the water from the desiccants. This concentrated desiccant canthen be used to dry the air either within the Dry Channel or outside theapparatus. To create a larger vapor drive difference between tile Wetand Dry Channels, a pressure drop must be created between them. Inaddition the Dry Channel may need to have heat added before, during orafter entering it and the Wet Channel may need to have water added to asurface both causing a greater vapor drive potential between thechannels.

[0046] The method may be used to create cool concentrated desiccant fordrying air and then using a more conventional cooling system in anotherprocess.

[0047] The core method can be efficiently used when working air isredirected from the Dry Channel into and through the Wet Channel, forexample, through a plurality of spaced perforations or permeable poresformed in the heat exchange surface.

[0048] It can help to increase the coefficient of heat transfer betweenflows of working air in the Dry and Wet Channels. Also, it can help totransport absorbed water (when we use solid desiccant material) from theDry to the Wet Channel.

[0049] The working heat exchange apparatus for effecting theabove-described method will have: 1) A jacket with inlets and outletsfor the Product Fluid and the Working Air or other fluids respectively.2) The Product Channels for the Product Fluid. 3) The communicable Dryand Wet Channels for the Working Air with a heat exchange plate with orwithout perforations or pores. 4) The Product and Dry and Wet Channelsare alternated and separated with plates. 5) A liquid distributor forchannels with moisture on the walls Such as a liquid desiccant or water.6) Collecting trays for this liquid. 7) Valves for proper regulation offluids in the channels. 8) Other components needed for specific functionand operation of the apparatus, if pressure regulation is needed.

[0050] Counter flow is theoretically the most efficient design, howeverthere are many designs that can be used to produce a more economicallyviable units using cross flow or some other combination of flow.

[0051] The plate or membrane, which is the heat exchange surface betweenthe channels, can be made of wick, plastic, metal or solid desiccantmaterials or compositions of these materials.

[0052] While the description of this apparatus incorporates verticalchannels for liquid wetting of airflow throughout the channel, there arevarious methods of moving liquids such as wicking, high air or vaporvelocity, enough partial vacuum to lift the fluid, inclined slopes, etc.Depending on the application and design, the apparatus can be used withpanels turned from horizontal to vertical.

DESCRIPTION OF THE DRAWINGS

[0053] The invention will now be described by way of preferred exemplaryembodiment thereof with reference to appended drawings, wherein similarparts have tile same reference numerals and in which:

[0054]FIG. 1 is a flow diagram of the present method forindirect-evaporation cooling where by the Product 2 is cooled in theProduct Channel 1 along side the Wet Channel 5 and when multiplechannels are used, the Dry Channels 3 of the adjacent cooling unit aswell.

[0055]FIG. 2 is a flow diagram of the present method forindirect-transpiration cooling where by the Product 2 is cooled with theuse of excess Evaporative Liquid 10 such as water that has been cooledand is used to cool the Product 2 in a separate Product Heat Exchanger39.

[0056]FIG. 3 is a flow diagram where a desiccant, 47, is used in the DryChannel 3 for drying the air and a separate regeneration apparatus, 56,is used to increase the concentration of the desiccant. The Wet Channel5 has water flowing down it and is cooled through evaporation. ProductChannel 1 is set along side and in heat transfer contact with the WetChannel 5 for Product cooling of some other fluid.

[0057]FIG. 4 is a flow diagram like FIG. 3 where a desiccant, 47, isused in the Dry Channel 3 for drying the air and a separate regenerationapparatus, 56, is used to increase the concentration of the desiccant47. The Wet Channel 5 has water flowing down it 10 and is cooled throughevaporation. Cool water 10 can be the Product 2.

[0058]FIG. 5 is a flow diagram like FIG. 3 but where the Product 72becomes part of the Working Fluid 4, which in most cases is air.

[0059]FIG. 6 is a flow diagram, where the heat exchange surface 9 of theDry Channel is made of or covered with solid desiccant material 46, forexample, silica gel, lithium chloride and etc. Regeneration of thedesiccant is by passing water through the wall of the heat transfersurface.

[0060]FIG. 7 is a flow diagram, where the heat exchange surfaces of theDry Channel 3 and also tile Product Channel 1 are made or covered withthe solid desiccant material 46.

[0061]FIG. 8 and FIG. 9 are flow diagrams, where the Dry Channel 3 orboth the Dry 3 and Product 1 Channels are made of or covered with soliddesiccant material 46 and tile walls of the Wet Channel 5 are wetted bya Evaporative Liquid 10 such as water without the formation of a movingliquid film.

[0062] FIGS. 1 to 9 contains: the Product Channel-1, the ProductFluid-2, Dry Channel-3, the Working Air-4, the Wet Channel-5 membranes,or walls-6 and 7 have heat exchange surfaces-8 and 9, moving film ofEvaporative Liquid such as water or a wet surface but non moving filmsuch as with a wick-10, the induced draft fan-11, a forced draft fan 74,pipes-41, 42, desiccant 46 and baffle 73.

[0063]FIG. 9(a) is similar to FIG. 9, except it has the working membranemade of or covered with solid desiccant.

[0064]FIG. 10 is a flow diagram, where liquid fuel 10 flows down alongthe walls of the Wet Channel 5: vehicle-61, fuel tank-62, internalcombustion engine-63, vehicle cab-64, exhaust gas-65, pipe-66, ducts-67and 68.

[0065]FIG. 11 is the same flow diagram like FIG. 10, where the Product2, such as air, being cooled is in a heat exchanger 39 using theEvaporative Liquid 10 after it's cooled.

[0066]FIG. 12 is a flow diagram, where liquid desiccant 47 flows downalong the heat exchange surface 9 of the Dry Channel 3 andsimultaneously liquid fuel 10 flows down along the walls of the WetChannel 5 and the product is cooled in the Product Heat Exchanger 39.

[0067]FIG. 13 is the same flow diagram like FIG. 12, where the Product2, such as air, being cooled is in the Product Channel 1.

[0068]FIG. 14 is a flow diagram where the wall 7 is crossed with a bankof heat pipes 69, evaporator sections 70 that are located in the DryChannels 3 and condenser sections 71 in the moist channel 5; the Product2 cooling takes place in the Product Heat Exchanger 39.

[0069]FIG. 15 is a flow diagram like FIG. 14 where a bank of heat pipes69 is used to span between the Wet Channel 5 and the in the ProductChannel 1.

[0070]FIG. 16 is a flow diagram where cooled desiccant 10 isconcentrated in the Wet Channels 5 and used for cooling. Theconcentrated desiccant is used for pre-drying the incoming air 4, andre-circulated in the Wet Channel 5.

[0071]FIG. 17 is a flow diagram similar to FIG. 16 where a ProductChannel 1 has been added.

[0072]FIG. 18 is a flow diagram similar to FIG. 16 where cold desiccant10 is used to dry and cool air or Product 2.

[0073]FIG. 19 is a flow diagram similar to FIG. 18 except dried air 2 isdirected to an apparatus for direct or indirect cooling 40.

[0074]FIG. 20 is a flow diagram with the same general concept as FIG. 16but where the desiccant dries the air in the Dry Channel 3 and then isdirected to the Wet Channel, desiccant from the Wet Channel is returnedto tile Dry Channel. The Product 2 is cooled in the Product HeatExchanger 39.

[0075]FIG. 21 is a flow diagram with the same general concept as FIG. 17but where the desiccant dries the air in the Dry Channel 3 and then isdirected to the Wet Channel, desiccant from the Wet Channel is returnedto the Dry Channel. The Product 2 is cooled in the Product Channel 1.

[0076]FIG. 22 is a flow diagram similar to FIG. 21, where the ProductFluid 2, for example, outside air, is transported to any kind of anapparatus for direct or indirect evaporative cooling 54.

[0077] FIGS. 16-22 contain: the Product Channel 1, the Product Fluid 2,Dry Channel 3, the Working Air 4, the Wet Channel 5 membrane, or walls 6and 7 have heat exchange surfaces 8 and 9, moving film of liquid such asdesiccant 10, the induced draft fan 11 and forced draft fan 74, the massand heat exchange apparatus 33 or air dryer 33, valves 34, 35, 36, 37and 38, the heat exchange apparatus 39, the apparatus for direct orindirect cooling 40 and 54, pipes 41, 42, 43, 44, 48 and 50, duct 45,pump 49 and 51, Dry Channel tray 52, Wet Channel tray 53, and baffle 73.

[0078]FIG. 23 shows cross flow direction of motion between the WorkingAir 4 in the Dry Channel 3 and the Working Air 4 in the Wet Channel 5.

[0079]FIG. 24 illustrates an example of a flow diagram, where workingair 4 is redirected from the Dry Channel 3 into and through the WetChannel 5.

[0080]FIG. 25 is a schematic view of the heat exchange apparatus foreffecting the method in accordance with the present invention (FIGS. 1,4, 5, 6, 7, 8, 9, 11), where: a jacket 12, inlet and outlet connectionsfor the Product Fluid 13 and 15, inlet and outlet connections for theWorking Air 14 and 17, adjustable dampers-16 and 21, tray for liquidfrom the Wet Channel 18, liquid distributor for the Wet Channel 19,valve for selection of liquid from the Wet Channel 20, the Wet Channels22, the Product Channels for the Product Fluid 23, the Dry Channels forthe Working Air 24, baffle-boards 25, 27 and 28, blind chamber 26,chambers 29 and 30, fan for the Product Fluid 31, induced draft fan forthe Working Air 32, forced draft fan 33, baffle 34.

[0081]FIG. 26 is a schematic view similar to FIG. 24 heat exchangeapparatus wherein the Dry Channels is equipped with a liquiddistribution system-58 for the Dry Channels-24, tray for this liquid-60,valve-59.

DETAILED DESCRIPTION OF THE INVENTION

[0082]FIG. 1 illustrates a flow diagram with a Product Channel 1 usedfor cooling a Product 2. The Product Fluid 2 is fed along the ProductChannel 1 of the heat exchange apparatus, and the Working Air 4, forexample, outside air is fed along the Dry Channel 3. The Wet Channel 5is arranged in heat transfer contact with Dry Channels 3 via membrane 7.The membrane 7 has heat exchange surface 9, limiting the correspondingDry Channel 3. The reverse sides of this membrane 7 are wetted with amoving film of the Evaporative Liquid, for example, water 10 using anyavailable method. The membranes 6 and 7 can be made of wick, plastic,metal, solid desiccants, micro sieve, etc. materials or composition ofthese materials. It is understood that the term membrane is used, butany structure that performs the function of separating Channel 3 fromChannel 5 or the working air from the product channel is suitable. TheWorking Air 4 is drawn to the induced draft fan 11 mounted at the outletof the Wet Channel 5 or in some cases the air is pushed through byforced draft fan 74. The Product Fluid 2 is directed along the ProductChannel 1, where it is cooled without changing its moisture content. Atthe same time the Working Air 4, is directed concurrently with respectto the Dry Channel 3 in contact with a heat exchange surface 9. In sodoing, the Working Air 4 is cooled, due to the heat absorption due toevaporation occurring in the Wet Channel, without any change to themoisture content of the Dry Channel air and then it is turned to the WetChannel 5, where it flows counter currently in contact with the moistsurfaces, for example, with wick or capillary-porous material beingwetted by Evaporative Liquid 10. As the Working Air 4 passes along theWet Channel 5 it is heated, moistened and is preferably drawn by theinduced draft fan 11 to the atmosphere or as in some cases forced by fan74. As the Working Air 4 passes along the heat exchange surface 9, it iscooled as a result of the heat exchange by the same flow passing alongthe surfaces of a Wet Channel 5 that are wetted by the movingEvaporative Liquid 10. In the Wet Channel 5, latent heat of evaporationis removed which results in the cooling of Working Air 4 on the wetsurface and eventually owing to heat transfer via the membrane 7 givingpre-cooling of Working Air 4 in the Dry Channel. Should outside airtaken directly from the atmosphere be used as the Working Air 4, passingthrough the Dry Channel 3, then by the time it has passed through theDry Channels and contacts the moisture in Wet Channel 5 it will havecooled down to near the dew point temperature of the Working Air. In sodoing, the Product Fluid 2 can be cooled in an ideal case to the dewpoint temperature by the evaporative action in the Wet Channel takinglatent heat from the heat exchange membrane between the product and theWet Channel. In actual fact, this temperature will be still higher dueto the Product Channel membrane 6 thermal resistances.

[0083] It follows from FIG. 1 that the length of the Dry Channel 3 isequal to that of the Wet Channel 5, although alteration and variousrelations of these channels' lengths are possible.

[0084] To increase the cooling potential, the Working Air 4 can beheated before, during or after it's passing along the Dry Channel 3,(FIG. 1). Increasing temperatures of the Working Air 4, before, duringand after passing along the Dry Channel 3, gives the possibility toincrease latent heat capacity, and thus, the efficiency of the exhaustedWorking Air 4 into the Wet Channel 5. This is due to the latent heathaving a larger effect on the enthalpy than sensible heat with a greatereffect as the temperature rises.

[0085] As the airflow passes along any surfaces, aerodynamic losses ofthe head always occur due to resistance. Therefore, in the withinembodiments, the value of the head of the Working Air 4 will decline asit moves along the heat exchange surface 9 in the Dry Channel 3,particularly when it turns 180 degrees and then as it travels over thewetted surfaces of the Wet Channel 5. This pressure drop will cause alowering of the vapor partial pressure of the air and in turn willreduce the dew point temperature of the air. Sometimes it is attainedthrough the use of resistance in the channels such as with corrugatedpanels oil small channel width, with baffles, valves, liquid flow etc.This, in turn, will facilitate more effective evaporation of water vaporinto this air to increase the cold production process of transpirationcooling.

[0086] In the method according to the invention it is expedient thatadditional aerodynamic resistance be created in order to enhance theevaporation cooling efficiency. Additional power consumption for the fanwill be much lower in many cases than the value of the positive effectobtained with an increased evaporation of water into Working Air 4. Itis possible to provide additional aerodynamic resistance and disruptionof stagnant surface layers of working fluids, for example, using variousperforations or pores or by heat exchange surfaces, by placing them inthe flow path. It is also possible to provide aerodynamic resistance bynarrowing this flow path, placing dampers in its path or restrictedpathways.

[0087] This yields a double advantage of a lower pressure in the Wetchannel 5 increasing the evaporation rate, and increasing the heattransfer rate in the Dry channel 3 where there is a lower heat transferrate as compared to the Wet Channel between the dry Working Air 4 andheat transfer surface 9. In addition to the alteration of the vaporpressure, the partial vacuum which is created by the induced draft fan11 can be used to increase the capillary action or passage throughperforations or pores, in some designs where wicking is used between theDry and Wet Channels or in the distribution of the liquid desiccant.

[0088] The invention makes use of a heat transfer membrane thatseparates two portions of a working gas flow channel. As seen in FIG. 1the gas depicted as 4 flows down channel 3 which we designate the drychannel and up channel 5 which we designate to be the wet channel. Theheat transfer membrane 7 is comprised of a thin material that allows thetransmission of heat across its horizontal width because of its thinconstruction. The heat transfer membrane 7 generally, through a giventhickness does not have good heat transfer ability relative to materialssuch as metal. However, due to its thin construction of the wallthickness between channel 3 and channel 5, heat is able to transfereasily and quickly from channel 3 to channel 5. The heat at any givenlocation on the membrane does not readily move along the surface of themembrane because of the materials' high resistance to heat transfer, ina direction other than across the thin membrane.

[0089] The result of this is that temperatures will vary along theheight or vertical distance shown in FIG. 1 and depicted in referencelevels AA, BB, CC, DD, EE, FF, and GG. The choice of the wall material,whether it is relatively impermeable to moisture or able to transmitwater or vapor as a micro-pore or perforated membrane, requires thisheat transferability parameter. The particular material may be paper,plastic such as Tyvek, sieve webbing or any common matter meeting theseparameters.

[0090] Within wet channel 5, water or other fluid is on the walls of thewet channel 5. The passage of the gas or working fluid 4 from its source74 through the dry channel 3 and into channel 5 and is shown ascounterflow. The wet channel 5, which has fluid on its walls, allows forthe use of evaporation and the heat of transformation or evaporation tobe transferred from the fluid, thus cooling the fluid. The exhaust gasesof the working fluid exits at 75. The gases in the wet channel 5 due toevaporation will cool the fluid and in turn the membrane 7 which will inturn cool the working gas in channel 3, the dry channel.

[0091] The working gas 4 in the wet channel will continue taking thevapor of the evaporation of the fluid until it reaches or nears itssaturation point. FIG. 1 at AA would be one temperature in the exhaustor wet channel side. That temperature would be transmitted through themembrane 7 to its counterpart in the dry channel side. Similarly thisoccurs at points BB and CC and through the various levels of FIG. 1. AtAA the working fluid at that point has had the least amount of time topickup evaporative vapor and thus the least opportunity to cool thefluid that would be instantaneously located at AA.

[0092] As you proceed further up the wet channel from BB to CC and on,tile temperature due to evaporation, will continue to be cooled at eachlocation.

[0093] Simultaneous with the continued evaporation which will cool thefluid at the level that the evaporation occurred, the fluid that hasbeen cooled at a given level will be moving downward as it moves. Theadditional effects of the fluid which has been cooled by evaporation andis moving downward is that fluid that had been at GG and cooled byevaporation through time will move downward to DD where furtherevaporation will occur and onward to AA and if any excess fluid is leftit exits the system. This flow allows the fluid at the level where it iscooled by evaporation through heat transfer to take heat from the drychannel 3 at that point and provide the fluid latent heat and additionalvapor pressure for further evaporation. Then further evaporation willcool the liquid more. Thus, the fluid continues to provide evaporationand take off heat of transformation. Further the lower temperature thathad been created at FF by evaporation will be transmitted by heattransfer to the dry channel and by flow downward to the lower levels ofthe membrane 7 where further evaporation will occur which, in turn, willfurther cool the concurrent side of the dry channel across the thinmembrane 7. Thus the cumulative impact at AA will be from evaporationthat has occurred above it and the transmission of that cooled fluiddown to the point AA as well as the evaporation that occurs at point AA.At GG the temperature or cooling will occur at GG solely by way ofevaporation. But by the working fluid being cooled, the stabletemperature at GG will be lower than outside ambient temperature.

[0094] The effect on the dry channel portion of the working fluid flow 4is that the working fluid in the dry channel will be cooled at GGbecause of the cooler temperature across the membrane 7. Similarly thiscooling will continue to occur to the working flow 4 as it progressesdownward from level GG, FF, DD, CC, BB and AA. Thus the dry channel flowwill be precooled before it turns at the bottom of FIG. 1 and proceedsupward through the wet channel. Due to the fall of the cool fluid in thewet channel along that side of the membrane 7 the lowest temperaturewill occur at the AA position. The total system will cool until itreaches a stable temperature. Likewise because of the heat transfer andthe pre-cooling that has occurred from levels GG through the drychannel, flow of the working fluid 4 will also be at its lowesttemperature at level AA.

[0095] Also shown on FIG. 1 is a third channel 1 that has a flow ofproduct gas or fluid. There is a heat transfer membrane 6 that separatesthe wet channel from tile product channel 1. Similar to the membrane 7this membrane is also of a material that does not provide good heatconductivity normally but because of the thin construction of the wallseparating channel 1 from channel 5 heat transfer readily occurs. Thismaterial, aside from meeting the environmental consideration of the WetChannel and the Product Channel, can be of any material, just likemembrane 7. The temperature transfer vertically or along the surface ofthe membrane 6 does readily occur. The flow of the product air is againcounter to the flow of the working gas in the wet channel, but it can beof any orientation. Again this provides the maximum amount of cooling tothe product gases. At point GG gases and the wet walls in the wetchannel have been cooled by the evaporation. This cools the liquid onthe surface of the membrane 7 and 6. The membrane 6 in turn cools theproduct in channel 1. At point AA the product is being cooled to itsmaximum similar to the cooling that occurred in the dry channel becauseof the combination of the evaporation at point AA, the pre-cooling ofthe Dry Channel air and the movement of cooled fluid down from positionsabove. It is understood that the orientation of the FIG. 1 and the useof the terms vertical and up and down are descriptive and not limiting.It is understood that the flow of the fluids in the wet channel may beaccomplished by means other than gravity.

[0096]FIG. 2 illustrates a flow diagram of the present method, whereexcess Evaporative Liquid such as water 10 flows down along the walls 6and 7 of the Wet Channel 5 to the Product Heat Exchanger 39 and coolsProduct Fluid 2 flowing through it.

[0097] In applications where the method of cooling the product does notuse excess evaporative liquid, the flow of fluid will be just equal tothe maximum evaporation occurring during the wet channel phase. Wickingto the entire extent of the wet channel would be ideal.

[0098]FIGS. 3 and 4 add a concentrated desiccant in the Dry Channel 3with a desiccant regeneration process out side the apparatus. This hasthe direct effect of lowering the humidity in the air allowing for lowertemperatures and added cooling capacity. The desiccant 47 on surface 9in Dry Channel 3 absorbs water vapor from the Working Air 4 andtransmits heat through the wall 7 to the water 10 of the wet channel 5evaporating into the Working Air 4. The continual cooling of thedesiccant 47 in channel 3 increases tile Working Air 4 dryingcapabilities.

[0099] The flow rate ratio with the working gas is described inLowenstein, U.S. Pat. No. 5,351,497 and is ideal at 1.0 gpm/ft^(z) in acounter flow design.

[0100] In higher humidity climates it is rational, FIG. 4, to establishthe process, wherein liquid desiccant 47 flows down along the heatexchange surface 9 of Dry Channel 3, and water 10 also flows down alongthe walls 6 and 7 of the Wet Channel 5 simultaneously. In addition,liquid desiccant 47, after its passing along Dry Channel 3 and the tray52, is directed by the pump 51 (via the pipe 55) to the regenerator 56,where moisture is vaporized from liquid desiccant and then it is broughtback (via the pipe 57) into Dry Channel 3. Herewith, liquid desiccant,before it's directing to regenerator 56, beforehand is heated. And water10, after it's passing along the Wet Channel 5 and the tray 53, isdirected back by the pump 49 (via the pipe 41) to the Wet Channel 5.

[0101] When liquid simultaneously flows down in Dry Channel 3 and theWet Channel 5 in the manner of moving fluid film 47 and EvaporativeLiquid 10 (see FIGS. 3-5), it significantly improves heat and masstransfer performances in each channel. This creates a more compact andeffective apparatus.

[0102]FIG. 5 illustrates the apparatus where a portion of the WorkingAir 4 is drawn off as the Product 72 and the rest of tile Working Air 4continues on in Wet Channel 5. This has the advantage of better heattransfer between the Product/Working Air than would there be in aProduct Channel 1 or Product Heat Exchanger 39 when dry cold air isneeded as a product.

[0103]FIG. 6 illustrates, an internal desiccant regeneration process inconjunction with a drying process wherein the heat exchange surface 9 ofDry Channel 3 is made or covered with any available solid desiccantmaterial 46, for example, silica gel, lithium chloride and etc. When theWorking Air 4 is passing through Dry Channel 3 in contact with a heatexchange surface 9, it reduces not only the temperature but alsohumidity of the Working Air 4, because solid desiccant material adsorbsthe moisture from this air. The cold and drier Working Air 4 is passedto the Wet Channel 5 through pressure reduction baffle 73, if needed,where it evaporates the water 10 creating lower temperatures thanoutside air dew point temperatures because the Working Air 4 has lesshumidity. In addition the heat of adsorption, which transports from DryChannel 3 via tile wall 7 to the Wet Channel 5, is increased due to thedirect contact of fluids through the wall 7. Herewith, this actionincreases heat and mass performances as in Dry Channel 3, as well as inthe Wet Channel 5

[0104] In some cases it is necessary to create a larger Pressure dropbetween the Dry 3 and Wet 5 Channels to realize the process with thefluids being used as the Working Fluid 4, Evaporative Liquid 10 anddrying liquid or solid 47. In this case a pressure reduction baffle 73must be placed between the Dry and Wet Channel and possible a forceddraft fan 74 at the inlet of Dry Channel 3.

[0105] In this method of indirect-evaporation cooling the walls 7 and 6can be made of wick, plastic, metal or solid desiccant materials orcompositions of these materials, with tile physical capability of heattransfer being less along the surface of the wall or membrane ascompared to the heat transfer rate across the thickness of the wallbetween the adjacent pathways. If the walls have some capacity oftransferring vapor or liquid across the thickness, a bias will becreated, by pressure or other means commonly known or developed in thefuture to bias this ability to be on a selected direction such as fromthe Dry Channel to the Wet Channel, or from the Product Channel to theWet Channel. This method gives unique possibility to organize the veryeffective heat and mass exchange processes between the Dry 3 and Product1 Channels and the Wet Channel 5, using the wick or solid desiccantmaterials for the walls 7 and 6, without presence of the waterproofpartition. First of all, it improves heat and mass transfer performancesin channels because wetted wick or solid desiccant materials have moreconductivity than other materials, due to the moisture passage into thematerial on tile Dry side and out of the material on the wet side. Alsoless heat resistance on the interface between airflow and the wall orthe liquid film or moving liquid film and a wall. Second, wick or soliddesiccant materials for the wall enables effective transport of adsorbedmoisture from Dry Channel 3 to Wet Channel 5 via the membrane. Thedifferences of the pressures between Dry Channel 3 and Wet Channel 5,aid this movement. Opposite direction of movement of liquid from the WetChannel 5 to the Dry Channel 3 and 1 is not possible, because pressurein the Wet Channel 5 is always less than pressure in the Dry Channels 3and 1.

[0106]FIG. 7 shows the same scheme like FIG. 6, wherein there is onlyone distinction, namely, the heat exchange surface 8 of the ProductChannel 1 also is made or covered with the solid desiccant material 46,for example, silica gel, lithium chloride and etc. When the ProductFluid 2, for example, outside air is passing through tile ProductChannel, solid desiccant 46 adsorbs the moisture from this air. Thiscreates not only cold (about the dew point temperature of dried air 4)but dryer air 2. The process of adsorption in Dry Channels 1 and 3 iscontinuous. Adsorbed moisture transports from Dry Channels 1 and 3 viathe walls 6 and 7 to the Wet Channel 5, because the pressure of air isalways less in the Wet Channel 5 than in the Dry Channels 1 and 3. Inaddition the density difference between the desiccant 46 and the water10, and the heat flux direction from desiccant 46 to water 10 will helppull the water from the desiccant to the Wet Channel 5.

[0107]FIG. 8 and FIG. 9 illustrate the flow diagrams of the presentmethod; wherein the walls 7 and 6 of the Wet Channel 5 are wetted bywater 10 without the formation of a moving liquid film with for instancethe use of a wick. Herewith, the heat exchange surface 9 of Dry Channel3 (FIG. 8) or the heat exchange surfaces 9 and 8 of both Dry 3 andProduct 1 Channels (FIG. 9) are made or covered with the solid desiccantmaterial 46, for example, silica gel, lithium chloride and etc. In thiscase the Product Fluid 2, for example, outside air can be cooled lowerthen the dew point temperature of the outside air. The advantage of nothaving a moving water film 10 is that there is no energy losses do tocooling water that is not directly evaporated allowing for additionalproduct cooling.

[0108]FIG. 9a is similar to FIG. 9 illustrating the flow diagram of thepresent method wherein the sides of the walls 7, which are located inthe Dry Channels 3 and/or the Product Channels 1 are made or coveredwith a solid desiccant material 46, such as silica gel, lithiumchloride, etc. The use of a solid desiccant sheet or membrane isdisclosed in U.S. Pat. No. 5,653,115. Similar materials are availablefrom manufacturers. The other side of these walls 7 are located in theWet Channel 5, but are not wetted by the Evaporative Liquid. Only WetChannel 5 side of walls 6 are wetted with Evaporative Liquid 10 such aswater, liquid desiccant or fuel. The advantage of this design is that itadsorbs water vapor from the Working Air 4 in the Dry Channels 3 and/orthe Product Air 2 in the Product Channels 1 via the walls 7 and 6 to theWet Channels 5.

[0109] The present method can be efficiently used also for airconditioning and cooling systems for vehicles, wherein the EvaporativeLiquid in the Wet Channel 5 is liquid fuel (see FIGS. 10-13).

[0110]FIG. 10 illustrates the same apparatus as in FIG. 1, whereinEvaporative Liquid 10 is a fuel, which is drawn from the fuel tank 62 ofa vehicle 61 and it is transported via a pipe 66 to the Wet Channel 5.Herein, liquid fuel 10 flows down along the walls 7 and 6 of the WetChannel 5. At the same time, the Working Air 4, for example, outside airis directed along Dry Channel 3 in contact with a heat exchange surface9. In so doing, the Working Air 4 is cooled without change in itsmoisture content and then it is turned to the Wet Channel 5, where itmoves counter currently in contact with the moving film 10 of liquidfuel. In the Wet Channel 5 the vapor evaporates from liquid fuel 10 intothe Working Air 4. As a result this contact, latent heat of evaporationis removed. As the Working Air 4 passes along the Wet Channel 5, it isheated through the heat exchange wall 7, and saturated by the vapor ofliquid fuel and an induced draft fan 11 pulls it through channel 5.Forced draft fan 74 is an optional but less desirable arrangement neededto accommodate actual apparatus physical design restraints. Hereon, thisfuel-air-mixture is directed via duct 67 to the internal combustionengine 63 of a vehicle 61. At the same time the Product Fluid 2, forexample, outside air is directed along the Dry Channel 1 in contact withthe heat exchange surface 8. Herein, outside air 2 is cooled ideally tothe temperature reached of the fuel/air mixture temperature created whenthe fuel evaporates in air, that the engine 63 requires.

[0111] After passing along tile Dry Channel 1, the Product Fluid 2 isdirected via the duct 68 to the cab 64 of a vehicle 61. The heatexchange surfaces 9 and/or 8 of Dry Channel 3 and/or the Product Channel1 can be made or covered by a solid desiccant material, for example,silica gel, lithium chloride and etc. (as this is seen from FIGS. 7-9).In additional, the walls 6 and 7 of the Wet Channel 5 can be wetted byliquid fuel 10 without formation of a liquid moving film (as this isseen from FIGS. 8 and 9).

[0112]FIG. 11 is the same flow diagram like FIG. 10, where the ProductFluid 2, for example, outside air is directed to heat exchange apparatus39 for heat exchange contact with cold liquid fuel 10, after its passingthrough the Wet Channel 5. Hereon, the cold air 2 is directed via theduct 68 to the cab 64 of a vehicle 61. In additional, the Working Air 4as the fuel-air mixture, after it's passing along the Wet Channel 5, isdirected via the duct 67 to the internal combustion engine 63 of avehicle 61.

[0113]FIG. 13 illustrates the same scheme like in FIG. 10, but whereinas the Evaporative Liquid is a mixture of water and fuel 10, which isselected from the fuel tank 62 of a vehicle 61, and it is transportedvia a pipe 66 to the Wet Channel 5. Herein, water and liquid fuel 10flows down along the walls 6 and 7 of the Wet Channel 5 or they arewetted by liquid fuel 10 without formation of a liquid moving film.Simultaneity liquid desiccant 47 flows down along the heat exchangesurface 9 of Dry Channel 3 and then it is directed to the regenerator56. Herein, moisture is vaporized from liquid desiccant 47 by heat ofexhaust gas 65 of a vehicle 61, and it is brought back into Dry Channel3. This drying of the Working Air 4 prior to passing through the WetChannel 5 increases the product cooling quantity and quality as itallows additional evaporation of water as well as fuel. Working Air 4passes along the Wet Channel 5 creating the fuel-air mixture and isdirected via the duct 67 to the internal combustion engine 63 of avehicle 61. Simultaneously the Product Fluid 2, for example, outsideair, after it's passing along the Dry Channel 1 is directed to the cab64 of a vehicle 61.

[0114]FIG. 12 is the same flow diagram like FIG. 13, where the ProductFluid 2, for example, outside air is directed to the heat exchangeapparatus 39 for heat exchange contact with cold water and/or liquidfuel 10, after its passing through the Wet Channel 5. Hereon, the coldproduct air 2 is directed via the duct 68 to the cab 64 of a vehicle 61.In additional, the Working Air 4 as the fuel-air-mixture, after it'spassing along the Wet Channel 5, is directed via the duct 67 to theinternal combustion engine 63 of a vehicle 61.

[0115] In FIGS. 10-13 water can be added along with liquid fuel, and forcertain in FIGS. 12 and 13 before it's passing along the Wet Channel 5increases the evaporative cooling by a combined water and liquid fuel 10in the Wet Channel 5. In addition it increases the water vapor in thefuel-air mixture, which is directed via the duct 67 to the engine 63,and it helps to improve the combustion process in the engine 63 of avehicle 61. As a result the exhaust gases from the engine have lesstoxicity.

[0116] In vehicles that do not use enough fuel to adequately cool theinterior, in electrical vehicles or other types of vehicles, water canbe evaporated 10 in Wet Channel 5 of FIGS. 12 and 13. This system willneed to be combined with a desiccant 46 in the Dry Channel 3, (FIG. 9)or another variation of the apparatus that dries the air.

[0117] Using the exhaust from the engine to preheat the air 4 enteringchannel 3 can effectively use waste heat to create a greater potentialenergy for cooler production.

[0118] Heat pipes can make an effective design within this method, seefor example FIGS. 14 and 15 where the walls 6 and 7 separate thechannels and a bank of heat pipes 69. Heat pipes such as those comprisedof a sealed vessel with a heat carrier inside. On one end, heat is takeninto the vessel by heat transfer boiling the heat carrier into vapor.The vapor moves to the cool section of the vessel where it condenses,giving up the latent heat and converting the vapor back to the liquidstate. The evaporator section 70 being located in the Dry 3 or Product 1Channels and condenser sections 71 are located in the Wet Channel 5.This effectively eliminates the need for a plethora of channels as theheat pipes transfer the heat. Additionally, the sections operate assurface irregularities to break up the boundary layers of the fluid. Inconventional units heat pipes are used for thermal heat recovery units.In the present invention desiccant 47 is sprayed on the evaporatorsection (or evaporator section of the heat pipes are covered by a soliddesiccant) of the heat pipes 70 of the bank of heat pipes 69 in the DryChannel 3 with Working Air 4 flowing over the pipes and giving up theheat of absorption as the air is dried. This heat travels through theheat pipes to the Wet Channel 5 and the condensing side of the heatpipes 71, where water 10 is sprayed on them with the Working Air 4traveling over the pipes and absorbing the water evaporation. Theevaporation liquid desiccant 47 is used more efficiently because theheat of absorption is dynamically transferred away from the Dry Channel3 to the Wet Channel 5, thus, reducing the absorption temperature andpositioning tile operation in a more favorable portion of the desiccantand moisture equilibrium map.

[0119] FIGS. 16-19 illustrates a flow diagram of the present method ofindirect-evaporation cooling where evaporative liquid 10 is a liquiddesiccant which flows down the Wet Channel 5 of walls 6 and 7. TheWorking Air 4 is first directed for dehumidifying by contact with aconcentrated liquid desiccant in a mass and heat exchange apparatus 33or Air Dryer 33 (FIGS. 16 and 17).

[0120] In this case, the Evaporative Liquid 10 is the desiccant used inAir Dryer 33 and is being regenerated to a higher concentration for usein the Wet Channel 5. The concentrated desiccant is then directed viathe pipes 41 and 43 (the valve 38 is opened and the valve 37 is closed)back to the mass and heat exchange apparatus 33. The hot but dry WorkingAir 4 coining out of Air Dryer 33 is transported via the duct 45 (thedamper 35 is opened and the damper 34 is closed) to Dry Channel 3. Thehot and weak desiccant 10 coming out of Air Dryer 33 is directed via thepipes 44 and 42 (tile valve 36 is opened) to the inlet of tile WetChannel 5. The valves 36, 37 and 38 are dedicated for regulation ofratio of quantity of liquid desiccant 10 coming to the inlet of the WetChannel 5 directly from of the outlet of the Wet Channel 5 (via thepipes 41 and 42) and from Air Dryer 33. The dampers 34 and 35 arededicated for regulation of ratio of quantity of the Working Air 4coining to the inlet of Dry Channel 3 from outside air (via the damper34) and from tile apparatus 33 (via the duct 45 and damper 35). Thisratio depends from regimes of working all system and the parameters(especially humidity) of outside air because outside air is energyresource for realizing of this method of direct-transpiration cooling.

[0121] To create the right conditions for tile regeneration of desiccantin the Wet Channel 5, heat may need to be added to the Working Air 4.The specific heat input is readily known by one familiar withregeneration of desiccants. With added heat in the Working air therewill be added potential energy for evaporation in the Wet Channel 5allowing additional water to be added to the desiccant 10.

[0122] FIGS. 16-19 represent the apparatus being used to cool andregenerate or re-concentrate the desiccant.

[0123]FIG. 16 illustrates a flow diagram of the present method, wherethe Product Fluid 2, is directed for heat exchange contact with liquid10, Product heat Exchanger 39. FIG. 17 uses a Product Channel 1 ratherthen a Product Heat Exchanger 39

[0124]FIG. 18 illustrates a flow diagram, where the desiccant 10, (likeon FIG. 16) but without the apparatus 39, is directed to Air Dryer 33.The Product Fluid 2 is passed through Air Dryer 33 where it is dried andcooled with cold desiccant. In this use the Wet Channel 5 becomes thedesiccant regenerator and may require heat to be added to the WorkingAir 4 for the process to work and/or a large pressure difference betweenthe Dry Channel 3 and the Wet Channel 5 caused by a pressure reductionbaffle 73 a forced draft fan 74 and a induced draft fan 11.

[0125]FIG. 19 illustrates a flow diagram of the present method, wherethe Product 2 is outside air after its mass and heat exchange contactwith liquid desiccant 10 in apparatus 33, is transported to any kind ofan apparatus 40 for direct or indirect evaporative cooling.

[0126] The present invention has the essential advantages, which areshown in FIG. 22. Herein, the liquid desiccant 10, which flows downalong not only the walls 7 and 6 of the Wet Channel 5, but also liquiddesiccant 47 flows down along the heat exchange surface 9 of Dry Channel3 simultaneously. As is clear from FIG. 20 Working Air 4, for example,outside air is directed along Dry Channel 3 in contact with liquiddesiccant 47. As the desiccant 47 dries the Working Air 4 the heat ofabsorption is transferred to heat exchange wall 7. In so doing, theWorking Air 4 is cooled, reduced in moisture content and then it isturned to the Wet Channel 5. In Wet Channel 5 it flows counter currentlyin contact with the regenerating liquid desiccant 10 that absorbs thisheat. To create the needed vapor pressure difference between the DryChannel 3 and the Wet Channel 5 a large pressure difference between theDry Channel 3 and the Wet Channel 5 is caused by a pressure reductionbaffle 73, a forced draft fan 74, and a induced draft fan 11 Liquiddesiccant 47, after it's passing along Dry Channel 3, (see FIG. 20)increases its temperature and moisture, and it is drained into tray 52.Hereafter, it is directed by the pump 51 (via the pipe 50) to the WetChannel 5, where this liquid desiccant flows down in the manner of themoving film 10 Liquid desiccant 10, after it's passing along the WetChannel 5, reduces its temperature and moisture and it is selected tothe tray 53 for the Wet Channel 5. Hereafter, it is directed by the pump49 (via the pipe 48) to Dry Channel 3, where this liquid desiccant flowsdown in the manner of the moving film 47. The parameters of tileincoming desiccant 47 to Dry Channel 3 (low temperature and moisture)help to improve the absorption process. Product Fluid 2 is directed tothe Product Heat Exchanger 39 for heat exchange contact with liquiddesiccant 10. Liquid desiccant 10 is directed from the heat exchangeapparatus 39 by the pump 49 (via the pipe 48) to Dry Channel 3. FIG. 21is like FIG. 20 except a Product Channel 1 is used in lieu of a ProductHeat Exchanger 39, (see FIG. 20.

[0127] To increase the Product cooling capacity tile Working Air 4 canbe heated prior to entering or moving through Dry Channel 3 and wateradded to desiccant 10 before Wet Channel 5.

[0128] Product 2 air may need to be further cooled in a separateevaporative cooling apparatus 54 as shown in FIG. 22.

[0129] FIGS. 1-22 illustrate the direction of movement of the WorkingAir 4 in Dry Channel 3 or the Product Fluid 2 in the Product Channel 1is parallel and in counter flow of the direction of movement of theWorking Air 4 in tile Wet Channel 5. The channels must be parallelhowever they can be in cross flow or some mix between cross and counterflow. For example, FIG. 23 shows cross flow directions between flows ofthe Working Air 4 in Dry Channel 3 and the Wet Channels 5. From a strictthermodynamic standpoint counter flow is more efficient however, thereare many designs that are more economical to fabricate and the geometrymore easily to work with when using cross flow.

[0130]FIG. 24 illustrates an example of a flow diagram of the presentmethod, where Working Air 4 is redirected from the Dry Channel 3 intoand through the Wet Channel 5, for example, through a plurality ofspaced perforations or permeable pores formed in the heat exchangesurface 9 of the working membrane 7.

[0131] This action can help to increase the coefficient of heat transferbetween flows of the Working Air 4 in the Dry 3 and Wet 5 Channels.Also, it can better help to transport absorbed water by solid desiccantmaterial 46 (see FIGS. 6-9 and 9 a) from tile Dry 3 to the Wet 5Channels.

[0132] The heat exchange apparatus with multiple channels for effectingthe method, according to the invention (see FIGS. 1, 2, 6-11 and 17-19),where the moving liquid film 10 flows down only along the Wet Channel5), is shown in FIG. 25. This apparatus comprises a jacket 12 with aninlet connection 13 for the Product Fluid and an inlet connection 14with an adjustable damper 21 for Working Air provided at one end of ajacket 12. At tile other end of a jacket 12 provisions are made for anoutlet connection 15 for the Product Fluid supplied to tile consumer.

[0133] The outlet connection 15 is fitted with an adjustable damper 16.Close to the inlet connection 13 of tile Product Fluid provision is madefor an outlet connection 17 for exhaust Working Air. The connection 17is made in tile upper portion of a jacket 12, which will become clearfrom subsequent description. In a jacket 12 are placed through WetChannels 22 for Working Air with a wetted capillary-porous material onsurfaces, which flows down liquid, for example, liquid desiccant. Theliquid desiccant is served in Wet Channels 22 from a liquid distributor19. Thereto as well in a jacket 12 are placed through Product Channels23 and through Dry Channels 24 limited by a moisture-proof material.

[0134] In the exemplary embodiment of the invention shown in FIG. 25tile Wet Channels 22 and also the Product Channels 23 and Dry Channel 24are made in the form, for example, of plates or corrugated plates.

[0135] It follows from FIG. 25, that Working Air passes through DryChannel 24 and then Wet Channel 22 with the Product Channel 23 betweenthem and in heat transfer contact with both. The Product Channels 23project with one end outside the limits of the Wet Channels 22 and arefixed by these ends in a baffle-board 25 to form a blind chamber 26limited by the baffle-board 25 and the walls of a jacket 12. The blindchamber 26 provides a tray 18 for liquid, for example, water after itspassing through the Wet Channels 22. The valve 20 uses for output ofthis liquid.

[0136] Further consideration of FIG. 25 shows that the Dry Channels 24for Working Air and the Product Channels 23 also project beyond the WetChannels 22 on the side of the inlet connection 13 of the Product Fluidand these projecting ends at the channels 23 and 24 are secured in thebaffle-boards 27, 28. Herewith a chamber 29 for removing waste WorkingAir is formed between the end surface of the Wet Channels 22 and thebaffle-board 27 and a chamber 29 communicates with the outlet connection17. Moreover, a chamber 30 is formed between the baffle-boards 27 and28, which communicate with the inlet 14 for introducing Working Air, forexample, the atmospheric air, although this chamber is optional and inthe present exemplary embodiment of the invention is dictated only bythe convenience of arranging the apparatus components.

[0137] Mounted in the inlet connection 13 is a fan or pump 31 (FIG. 25)for forcing the product, for example air or some other gas or liquidthrough the Product Channels 23. It is obvious that a pump or any othermeans known to those familiar with transporting other media can be usedto inject or convey liquid. It is clear from FIG. 25 that in the outletconnection 17 there is mounted an induced draft fan 32 for transportingWorking Air.

[0138] The above-described heat exchange apparatus operates as follows.A fan 31 injects the Product Fluid, for example, air, thus conveying theair along the Product Channels 23. As the air passes along thesechannels, it is cooled without a change in its moisture content and thenvia the outlet connection 15 is supplied to the consumer. The adjustabledamper 16 regulates the flow rate of the Product Fluid.

[0139] Working Air is simultaneously fed via the inlet connection 14where the forced draft fan 33 can be mounted, in the given case it isthe atmospheric air, flowing along the Dry Channels 24. At the sectionof the Dry Channels 24 being in the chamber 29 this air is previouslycooled do to the heat exchange with the air being fed to the chamber 29from the Wet Channels 22. Here, the air moves in cross-flow with respectto the channels 24 and is pulled off by a fan 32 to the atmosphere viathe outlet connection 17.

[0140] Having previously cooled in the channels 24 at their sectionsarranged in the chamber 29, the flow of Working Air is further cooled asit moves along the channels 24 to account for the evaporation of water,in the Wet Channels 22.

[0141] In the blind chamber 26 the Working Air is turned 180 degrees, asis shown by arrows in FIG. 25, to head for the Wet Channels 22.

[0142] As the Working Air flows in the Wet Channels 22, heat exchangeoccurs with the Product Fluid moving in countercurrent in the DryChannels 24 and the Product Channels 23 via the walls of these channels.As a result of such processes the flow of the product and Working Air iscooled to the dew point of the air entering without a change in itsmoisture content. The Working Air in the Wet Channels 22 is heated (as aresult of heat extraction from Product fluid (air) being cooled in theProduct Channels 23 and from itself after passing through the DryChannels 24,) and is moistened (as a result of water evaporation in theWet Channels 22.) Thereupon, the Working Air, coming out of the WetChannels 22, enters the chamber 29, where it cross-currently comes intoa heat exchange with both fluid (air) being cooled in the channels 23and the incoming flow of the Working Air in the channels 24. A result ofthis heat exchange contact such that the both flows (in Product Channels23 and Dry Channels 24) are precooled, while the Working Air (beingremoved from the Wet Channels 22) is heated about to temperatures ofincoming flows and in this condition is pulled off into the atmosphereby means of a fan 32 via the outlet connection 17.

[0143] In the heat exchange apparatus, according to the invention, theproduct fluid and the Working Air are separated from each other. Thismakes it possible to transport the Working Air with the aid of aninduced draft fan 32, which enables one to use the head loss in thecooling flow to intensity evaporation cooling.

[0144] Because during the passage of the Working Air first along the dry24 and after the wet 22 channels as a result of the effect of differentaerodynamic resistance, its head will decline (particularly, after theturn 180 degrees into the Wet Channels 22) the pressure drop in the flowcore results, respectively, in a decline of partial pressure of watervapor. This, in turn, enhances the effect of moisture evaporation intotile flow, which leads to greater efficiency of cooling the fluid.

[0145] In the above-described heat exchange apparatus it is expedientthat the Dry Channels 24 for Working Air be restricted to a developedheat exchange surface. This brings about a more substantial decline inthe head of the Working Airflow increasing the efficiency of cooling,and simultaneously increases the specific value of the heat exchangesurface, which reduces the overall dimensions of the apparatus andenhances the efficiency of cooling.

[0146]FIG. 26, is like FIG. 25, (see also FIGS. 3-5, 12-15, 20-22,)where the moving liquid film 10 flows down not only along the WetChannels 5 but also along the Dry Channels 3 simultaneously but with theadded ability to wet the Dry Channels with a liquid such as a desiccant.In the same way the Product Channel and could have this wetting systemadded also. The dry channels have had wetting system 58 added withliquid collection system added 60 with piping and valve 59 to be usedfor redistribution.

[0147] There are several designs where the increase in pressure dropbetween the Dry and Wet Channels is desirable and to that end a pressurereduction baffle 34 is shown. The most obvious uses for this baffle arewhen the regeneration of the desiccant is used in tile Wet Channels 22and a drying desiccant is used in the Dry Channels. The combination ofpressure reduction baffle 34 and forced draft fan 33 cause a largedifference in pressure and therefore large difference in vapor pressurebetween the Wet and Dry Channels allowing the drying of air in the DryChannel 24 and evaporation of water from the air in the Wet Channel 22.This same pressure difference may also be needed when a solid desiccantis used in the Dry Channel and water is used in the Wet Channel aspressure difference will create a vapor drive from the Dry to WetChannel forcing moisture through the porous walls from the soliddesiccant to be evaporated in the Wet Channel.

[0148] Sometimes, it is expedient when the plates of the heat exchangeapparatus between the Dry 24 and Wet 22 Channels for Working Aircomprise the perforations or permeable pores.

[0149] The present heat exchange apparatuses can work alone and togetherwith conventional heat and mass exchange equipment depending on theclaims of the present method would like to be realized.

[0150] In the present method of indirect-evaporation cooling this heatexchange apparatus, according to the invention, it is possible to coolair, gas, refrigerant, steam, liquid, and any material, which can betransported along channels. The different variations of this apparatusare useful because they permit cooling gaseous, liquid and dispersedmaterials without high-energy cost for cooling. In additional all thesematerials can be cooled lower then the dew point temperature of outsideair without using high energy cost of complex refrigeration machines.This process of cooling in the present method of indirect-evaporationcooling and a heat exchange apparatus uses significantly less energy dueto the use of natural psychometric difference of temperature andmoisture of outside air.

COMPARATIVE EXAMPLE

[0151] For purposes of illustrating the advantages of the apparatus andmethod disclosed herein, the applicants take the results using theapparatus disclosed in Russian patent No. 2046257 (Maisotsenko) [copiedin U.S. Pat. No. 5,187,946]. We compare the results using the apparatusshown in FIG. 3 in Table #1.

[0152] The materials as used in the test of FIG. 3 are a wickingmaterial on the wet surfaces made of cellulose blended fiber sold byAhistrom Paper Group, Grade 1278 (0.2969 mm thickness), backed, for thedry side of the membrane, with 5 mil Mylar callendered with an adhesive(appropriate for the material).

[0153] This material is the best readily available product, though othermaterials may be used, such as an absorbent material, such aspolypropylene with a polyethylene coating which was available fromAhistrom as Grade 4002. Another combination, using polyethylene coatingon the Grade 1278, would have additional advantages.

[0154] The advantage of Grade 1278 is that it is specifically a wickingmaterial with a high klein test of approximately 55, compared topolypropylene whose klem test is 26.

[0155] If the working air 4 enters the apparatus at 122 M³/hour having adry-bulb temperature (tdb) of 35.4° C. and a wet-bulb temperature (twb)of 22.8° C. The stream of the working air 4 flows through the drychannel 3 where the desiccant 47 (aqueous lithium chloride solution withconcentration 43.4%) absorbs water vapor from the working air 4 andtransmits heat through the wall 7 to the water 10 of the wet channel 5evaporating into the working air 4.

[0156] The continual cooling of the desiccant 47 in channel 3 increasesthe working air 4 drying capabilities.

[0157] Simultaneously the product air 2 (outside air) enters the productchannel 1 at 125 M³/hour having the same temperature parameters likeworking air 4. The stream of the product air 2 after its passing throughproduct channel 1 having a dry-bulb temperature (tdb) of 10.1° C. andwet-bulb temperature (twb) of 8.2° C. The aerodynamic losses of thetotal air streams from inlet (for this test was used one fan) todischarge is 127 Pa. A 25 watt fan propels the air. The total surfacearea of tile heat transfer surface is 0.672 M².

[0158] For purposes of comparison, the apparatus disclosed in Russianpatent No. 2046257 ( and the same U.S. Pat. No. 5,187,946) was used tocool a stream of ambient air (working air) having the same approximatethermal characteristics. An incoming working air flow of 240 M³/hourhaving a dry-bulb temperature 35.1° C. and a wet-bulb temperature of22.6° C. was directed to an equal surface area of 0.672 M². After thedry channel pass the incoming flow is split with the redirectedsecondary air stream of 119 M³/hour going to the wet channel resultingin 121 M³/hour (as a product air) directed to the user. When thisapparatus was employed as taught, aerodynamic losses of 105 Pa resultedand necessitated a 22 watt fan. The product air directed to the user hada dry-bulb temperature of 19.1° C. and a wet-bulb temperature of 17.6°C. By comparing the claimed and known methods we can see that we can getmuch less temperature of the product air (10.1° C.) compare with 19.1°C. using known method. The following Table #1 summarizes the abovecomparison and additional regime with another parameters of outside airwherein the initial air is drier. Likewise, the method as claimed hereresults in lower temperature of the product air. TABLE #1 Air FlowTemperature, degree °C. M^(e)/hour Working Air Product Air PressureWorking Product Inlet Outlet Drop, Energy for Air Air tdb twb tdb twb PaFan, watt 1. Claimed Method 122 125 35.4 22.8 10.1 8.2 127 25 (see FIG.3) Known (*) Method 240 121 35.1 22.6 19.1 17.6 105 22 U.S. Pat. No.5,187,946 Or Russian Pat. No. 2046257 2. Claimed Method 125 127 26.516.7 7.7 4.0 127 25 (see FIG. 3) Known (*) Method 239 120 26.1 16.3 14.811.9 105 22 U.S. Pat. No. 5,187,946 Or Russian Pat. No. 2046257

[0159] The Comparison illustrates the benefits of indirect cooling andby a single flow, first pre-cooled in the dry channel, and dehumidified,and then used in the wet channel to remove heat into latent heat in thevapor. The product is indirectly cooled by the wet channel flow.

1. A method of indirect-transpiration cooling, which comprises: a)passing a Product Fluid in a product channel; b) Having a surface withsaid product channel, having a wall created by a first side of a firstmembrane, c) Having a Dry Channel with one of its walls being a firstside of a second membrane, d) Having a Wet Channel comprised of at leasttwo walls, one being the second side of the first membrane and thesecond being the second side of the second membrane, e) Having the wallsof the Wet Channel being supplied with evaporative liquid, f) Passingworking fluid first through the Dry Channel, and then in counter flow tothis direction, through the Wet Channels, g) Having a heat exchangemechanism between the Working Fluid in the Wet Channel, and the ProductFluid in the Product Channel, h) Having a heat exchange mechanismbetween the working fluid in the Dry Channel and the Wet Channel.
 2. Amethod according to claim 1, wherein the Working Air flow is beinginduced from the Wet Channel.
 3. A method according to claim 2, whereina pressure drop is created between the Dry and Wet Channels.
 4. A methodaccording to claim 1, wherein the Working Air path along the Dry Channelwall is not equal to that along the Wet Channel wall.
 5. A methodaccording to claims 1, a Product Heat Exchanger exchanges heat betweenthe Product and excess Evaporative fluid from the Wet Channel.
 6. Amethod according to claims 1, wherein a liquid desiccant flows over theDry Channel wall of the second membrane.
 7. A method according to claim6, wherein liquid desiccant, after its passing over the Dry Channel, isdirected outside the apparatus for regeneration, and subsequent reuse.8. A method according to claim 1, wherein the second membrane is porousbetween the Dry and Wet Channels to allow working fluid to pass.
 9. Amethod according to claim 1, wherein some part of the Working Air, afterpassing through tile Dry Channel, is withdrawn and used as the ProductFluid being cooled.
 10. A method according to claim 1, wherein the wallsof the second membrane of the Dry Channels has solid desiccant material.11. A method according to claim 1 wherein at least one of the walls ofthe Wet Channel are wetted by liquid desiccant.
 12. A method accordingto claim 1, wherein the Evaporative Liquid is a liquid fuel that wetsthe Wet Channel.
 13. A method according to claim 13, wherein the WorkingAir passing through the Wet Channel creates a fuel-air mixture which isdirected to an internal combustion engine.
 14. A method according toclaim 1, wherein exhaust gas from an engine is used to heat the WorkingAir before it enters the Wet Channel.
 15. A method according to claim 7,the regenerator, uses heat of exhaust gas of an engine.
 16. A methodaccording to claim 12 wherein water is added to fuel and is used as theEvaporative Liquid in the Wet Channel.
 17. A method according to claim1, wherein the heat exchange surfaces mechanism are one or more heatpipes, with evaporator section located in the Dry Channel and condensersection in the Wet Channel, and evaporation section in the ProductChannel and the condensation section in the Wet Channel.
 18. A methodaccording to claim 1, wherein the Evaporative Liquid is a liquiddesiccant which is on the Wet Channel walls.
 19. A method according toclaim 18, wherein the Working Air, before passing along the Dry Channel,is exposed to the liquid desiccant, and then this liquid is directed tothe Wet Channel as the Evaporative Liquid.
 20. A method according toclaim 18, wherein the liquid desiccant is re-circulated to the WetChannel.
 21. A method according to claim 19, wherein at least some partof the Working Air, after its contact with a desiccant is directed tothe Dry Channel, and the remainder is used for Product air.
 22. A methodaccording to claim 18, wherein at least some of the liquid desiccantafter its passing along the Wet Channel, is directed to the Dry channel,and at least some of the liquid desiccant after it's passing along theDry Channel, is directed to the Wet Channel.
 23. A method according toclaim 1, wherein the Product Fluid, after cooling is transported to anapparatus for cooling of another material.
 24. A method according toclaim 1, wherein the Evaporative Liquid is heated.
 25. A methodaccording to claim 1, wherein the Working Air is heated.
 26. A methodaccording to claim 1, wherein the direction of movement of the fluidsruns by a means other than counter flow between the flow in the WetChannel and the Dry Channel and the Product Channel.
 27. A method,according to claim 1 wherein Working Air is redirected from the DryChannel into and through the Wet Channel, through a plurality of spacedperforations or pores formed in the second membrane.
 28. A heat exchangeapparatus wherein: a) There is a means to cool working fluid byevaporation of an evaporative liquid, b) A means to conduct heat from aproduct fluid to the working fluid, c) A means where Dry working fluid,before it starts evaporating the evaporative fluid, is pre cooled byheat transfer with the working fluid that is cooling by way ofevaporating of an evaporative liquid.
 29. A heat exchange apparatuscomprising: a) A jacket containing separate passages for Working Fluidand Product Fluid, b) Inlet and outlet for Working Fluid c) Inlet andoutlet for Product Fluid, d) Working fluid passes through a firstpassage, with a Dry Channel first, and a second Wet Channel, e) TheProduct Fluid passage shares a first membrane with the Wet Channel partof the Working Fluid passage, the first side is one wall of the productpassage way, and the opposing second side is one wall of the WetChannel, f) A second membrane separates the Dry Channel from the WetChannel of the Working Fluid passageway, g) A communication passagewayfor the Working Fluid from the Dry Channel to the Wet Channel, h) Atleast one wall of the Wet Channel is supplied with an evaporativeliquid, i) The flow of the Working Fluid in tile Dry Channel is counterto the flow of the Working Fluid in the Wet Channel, j) The flow of theProduct Fluid is counter to the flow of the Working Fluid in the WetChannel, k) Having a heat exchange mechanism between the Dry Channel andthe Wet Channel, l) Having a heat exchange mechanism between the ProductChannel and the Wet Channel.
 30. The apparatus of claim 29 wherein theheat transfer mechanisms are the first and second membrane.
 31. Theapparatus of claim 29 wherein the heat transfer mechanisms are heatpipes.
 32. The apparatus of claim 29 wherein the evaporative liquid isfuel.
 33. The apparatus of claim 29 wherein the evaporative liquid isliquid desiccant.
 34. The apparatus of claim 29 wherein the secondmembrane is solid desiccant.
 35. The apparatus of claim 29 wherein theProduct Channel is separate and passes in heat transfer connection withan excess evaporative liquid from the Wet Channel.
 36. The apparatus ofclaim 29 wherein there are more than one set of Dry, Wet and ProductChannels.
 37. The apparatus of claim 29 wherein the evaporative liquidis fuel with water.
 38. The apparatus of claim 29 wherein theevaporative liquid is liquid desiccant which first flows over the DryChannel side of the second membrane.
 39. The apparatus of claim 29wherein the working fluid is heated before it enters the Wet Channel.40. The apparatus of claim 29 wherein the membranes have multiplepassageways for fluid to pass from the Dry Channel to the Wet Channel.